26 results about "Triangular element" patented technology

The invention belongs to the technical field of airplane structure strength digital twinborn model construction, and particularly relates to an airplane structure finite element calculation result data noise reduction method, which comprises the following steps: step 1, preliminarily identifying deformity units including triangular units and high slenderness ratio units; identifying the triangular units based on the continuity of the node numbers; identifying a high slenderness ratio unit based on the side length; 2, defining a stress concentration area, and removing units in the stress concentration area from the deformed units; defining a stress concentration region including a hole edge, a fillet, a boundary constraint position and a region where a concentrated load applying position is located; 3, calculating the gradient of the deformity units, and removing units in a real physical gradient field from the deformity units; step 4, carrying out noise reduction processing on the calculated value of the malformation unit; and smoothing the calculated value of the malformed unit, or removing the calculated value of the malformed unit.

The invention relates to the technical field of numerical simulation of rock dynamics, in particular to a numerical simulation method and system for the whole process of ore rock fracture based on FDEM impact loads.The method comprises the steps that a continuous medium structure is discretized into a finite element network composed of triangular units through FDEM, and an ore rock impact test model is constructed; setting material parameters and impact speed boundary conditions according to the ore rock impact test model; a normal contact force calculation model and a tangential contact force calculation model are established according to material parameters and impact speed boundary conditions, and coordinates and speed updating results of triangular unit nodes are obtained in combination with the Newton second law and the calculation models; and performing visual analysis based on the coordinate and speed updating result, and outputting crack propagation, stress field and energy evolution results under the impact load. The method can accurately simulate the crack propagation, the fracture mode and the energy evolution law of the ore rock under the impact load, quantitatively researches the crushing characteristics and the energy evolution law of the ore rock, and provides a calculation method for the research of the crushing mechanism of the ore rock.

The invention relates to an antenna grid installation method for antenna layout design, and belongs to the technical field of electromagnetic compatibility and antennae, and the method comprises the steps: importing a grid model file of a large-size platform and an antenna, and reading a grid model to obtain a point coordinate list and a triangular unit list of the platform and the antenna; reading a starting point coordinate, a termination point coordinate, a voltage amplitude and a phase of an excitation voltage source of the antenna; establishing an antenna initial coordinate system, setting the main radiation direction of the antenna to establish a surface local coordinate system on the surface of the platform, and performing point matching on the model; and mounting the antenna grid model and the excitation source on the surface of the platform. According to the method, direct processing of complex grids is supported, limitation of traditional CAD modeling is broken through, subdivided discrete grids can be directly operated, and model reconstruction is avoided; through normal offset control and local coordinate system mapping, the normal function of the installed antenna is ensured, and the installation efficiency can be significantly improved on the premise of maintaining high-precision electromagnetic characteristics.

The present application relates to the technical field of machining, in particular to a free curved surface machining track generation method based on conformal mapping, which first selects an input three-dimensional triangular mesh curved surface; then uses a boundary-first unfolding algorithm to unfold it into a two-dimensional parameter domain triangular mesh plane, so that the obtained two-dimensional parameter domain triangular mesh plane is rectangular, and the deformation generated by the mapping is minimal; the next step is to deform the shape of the two-dimensional parameter domain triangular mesh plane to the size of the design area; after a designer plans a two-dimensional machining track on the design area, i.e. the deformed two-dimensional parameter domain triangular mesh plane, the machining track is discretized into a plurality of machining track points, and the barycentric coordinates of the machining track points in the corresponding triangular elements of the two-dimensional parameter domain triangular mesh plane are calculated, and finally the machining track points are inversely mapped onto the input triangular mesh curved surface, so that the input three-dimensional machining track is obtained. The present application solves the shortcomings of the prior art and can adaptively generate a corresponding spatial machining track on a three-dimensional curved surface.

The application discloses a kind of multivariate time series unsupervised dimension reduction method based on global-local divergence, it includes the following steps: S1, the covariance matrix of multivariate time series is calculated, the upper triangular element of covariance matrix is extracted, it is combined as feature sequence, obtain the feature set Fea of multivariate time series={f i |i=1,2,…,n};S2, using k near neighbor and Euclid Distance (Euclid Distance, ED) measure is established neighborhood set N k (f i )={f j |j=1,2,…,k};S3, after finding the neighborhood of each sample point, the neighborhood center sequence m i Of each feature sequence f i In feature set is calculated;S4, with the neighborhood variance of sample point after projection, local divergence is characterized.First, the variance of each sample point neighborhood set after projection is calculated, then the sum of the accumulation of these variances is obtained, to obtain local divergence;S5, according to the field center point obtained in step S3, the variance of field center point is calculated to obtain global variance.Finally, the low-dimensional projection sequence obtained by the experimental result shows that the method can represent original MTS, and obvious dimension reduction is realized.

This invention discloses a lightweight deep neural network array direction finding method based on data redundancy removal, which solves the problem that the traditional RDNN direction finding method has a large number of deep neural network nodes and cannot achieve network lightweighting. The method performs redundancy removal operation on the upper triangular elements of the covariance matrix, simplifies the number of subsequent hidden layer nodes, reduces the computational complexity of the model, and ensures that the direction finding accuracy of the model is not lost, thus realizing high-precision direction finding of lightweight deep neural networks.

The invention discloses a two-dimensional interferometer direction finding method based on a multi-frequency sparse area array. The method mainly solves the problems that in the prior art, the array arrangement space size is limited, and the two-dimensional DOA estimation precision is poor in a low signal-to-noise ratio scene. Comprising the following steps: 1) constructing a sparse plane physical array; 2) carrying out channelization processing on the broadband signal received by the antenna; 3) acquiring a vector signal model of the mapped channel by taking the center frequency of the Lth channel signal as a reference; 4) selecting effective channel data from L-1 channels, mapping all the center frequencies of the effective channel data to the center frequency of the Lth channel signal, and combining the signals; 5) calculating the covariance of the signal, and extracting the phase of a triangular element on the matrix; and 6) selecting a phase difference corresponding to the virtual baseline from the extracted phases, and realizing two-dimensional interferometer unambiguous direction finding by using a long and short baseline method. According to the method, two-dimensional DOA high-precision estimation can be effectively realized, and the method can be used for realizing two-dimensional direction finding of a target by a small unmanned aerial vehicle in a low-signal-to-noise-ratio environment.

The embodiment of the invention provides an STL (Standard Template Library) grid region division and re-subdivision method and device based on feature preservation. The method comprises the following steps: acquiring an initial grid container; subdividing triangular units in the initial grid container based on a longest edge bisection algorithm; the subdivided triangular units are stored in a subdivision grid container; feature boundary extraction is carried out on triangular units in the subdivided grid container in a dihedral angle threshold value judgment mode; on the basis of the feature edges of the triangular units in the subdivided grid container, performing feature curved surface division on the triangular units in the subdivided grid container through a curved surface division algorithm based on depth-first search to obtain a plurality of feature curved surfaces; and through harmonic mapping and an AFT-Delaunay method, parameterization is carried out on the characteristic curved surface, and mesh generation of the characteristic curved surface is completed. In this way, key geometric features such as sharp edges and ridges of the model can be accurately recognized, the dependence on the initial grid quality is reduced, and the generated grid quality is greatly improved.

The application relates to a method for generating a body grid based on radial growth of a cylindrical surface grid, in the field of electromagnetic engineering, and the method comprises the following steps: reading cylindrical surface grid data, including a point list P containing three-dimensional coordinates of N p points, a triangular element list E containing vertex indexes of E e triangular elements, and an element material list M; screening target elements through material matching; establishing a local coordinate system satisfying the right-hand rule and the orthogonal normalization condition of a vector, and performing coordinate transformation; performing radial mapping on the vertices of the screened elements; inversely transforming the mapped points to a world coordinate system; and generating a body grid, and converting a six-vertex triangular prism into three four-vertex tetrahedron elements by using a topological decomposition method. The electromagnetic calculation precision is improved: in electromagnetic field design calculation, the cylindrical radial grid growth technology makes the grid resolution in a strong field area multiply, and the calculation error of a resonance frequency is less than or equal to 0.3%.

The application discloses a method for implanting a large deformation plastic element based on FDEM in a non-rotating reference system, which comprises the following steps: obtaining a deformation rate in a rotating configuration and a rotation matrix based on the node coordinates of a triangular element; obtaining the deformation rate in a non-rotating configuration based on the deformation rate in the rotating configuration and the rotation matrix; determining an elastic trial stress, determining a material state in combination with a yield function, obtaining a true stress, and performing rotation mapping of an original reference configuration to obtain a true Cauchy stress; according to FDEM calculation, calculating contact force and force caused by cohesive force elements, and then uniformly converting the contact force and the force into node force; updating the node velocity and the position in the current time step through Newton's second law; and entering the next time step. The application introduces the calculation of a stress tensor in a non-rotating reference system, rotates the stress tensor, maps the stress tensor to the original reference system, and realizes the accurate simulation of plastic behavior in the wired-discrete element in combination with a yield function and a plastic flow rule.

The application provides a coarse-grained aggregate mechanical behavior continuous-discontinuous numerical calculation method, including: establishing a numerical model of coarse-grained aggregate, the numerical model including a constant strain elastic triangular element and an initial thicknessless cohesive force element distributed along the boundary of the triangular element; determining the constitutive relation of the cohesive force element in the numerical model under a continuous deformation analysis framework; determining the contact relation between discrete triangular elements in the numerical model under a discontinuous deformation analysis framework; obtaining a continuous-discontinuous coupling model of the coarse-grained aggregate based on the determined constitutive relation and contact relation, inputting boundary constraint conditions and external loads into the continuous-discontinuous coupling model according to actual working conditions, and performing simulation calculation to obtain the mechanical properties and deformation failure forms of the coarse-grained aggregate under external loads. The application establishes a corresponding numerical model through digital image analysis and recognition technology, completes continuous-discontinuous coupling calculation of the mechanical behavior of coarse-grained aggregate, and takes into account solving accuracy and calculation efficiency.

This application discloses a two-dimensional DC electric field forward modeling method, apparatus, electronic device, dielectric, and product. The method includes: taking the variational problem of a two-dimensional wavenumber domain point source DC electric field as the research object; dividing the model region of the dielectric model into several triangular elements and expanding the model region with a sparse mesh; reading the conductivity and potential of the principal nodes in each triangular element, and representing the conductivity and potential with quadratic interpolation shape functions to obtain a discrete model; constructing a system of linear equations based on the discrete model and the coefficient matrix of each triangular element; solving the system of linear equations to obtain the wavenumber domain forward modeling result; and performing an inverse Fourier transform on the forward modeling result to obtain the spatial domain electric field potential. The method increases the number of nodes in the mesh during model region meshing, reduces computation time by expanding the model, and utilizes more node property information through biquadratic interpolation of conductivity and potential within the mesh, thereby improving the accuracy of the two-dimensional DC electric field forward modeling fitting.

This invention provides a quasi-regular double-six discontinuous triangular mesh construction method for searching potential slope sliding surfaces, comprising: iteratively generating a quasi-regular initial triangular mesh adapted to the slope model boundary; locally dividing into six meshes to generate a six-directional arrayed topological mesh; constructing a data format of six-node triangular elements and high-order discontinuities; and solving the potential slope sliding surface using a second-order cone programming model. This invention adapts to the geometric boundaries of discrete slope models and meets the special requirements of the quasi-regular double-six discontinuous triangular mesh, forming a six-directional continuous discontinuous mesh structure within any small region. Furthermore, the double-six discontinuous mesh can be further pre-defined with local partitions, reducing resource consumption of mesh elements in non-critical areas. Applied to the upper limit finite element method of limit analysis, it achieves high-precision searching of potential slope sliding surfaces through rapid solving of the second-order cone programming problem, thus reducing computational burden while maintaining search accuracy.

This invention discloses a parameterization method for non-convex domains of complex surfaces generated by edge suppression. The method includes: performing edge suppression processing on an industrial part model to extract an initial 3D network of the geometric surfaces obtained after edge suppression; performing two-point constraint conformal parameterization on the triangular elements in the initial 3D network; detecting and removing self-intersections, parameterizing again, and repeating this step until no self-intersection regions exist; detecting and correcting element normal vector flips, parameterizing again, and repeating this step until no element normal vector flips exist, at which point the parameterization ends. This invention achieves non-convex domain parameterization of spatial triangular networks of complex surfaces generated by edge suppression. By fully considering the curvature characteristics of the 3D surface, it avoids the drawbacks of generating large distorted meshes, and can meet the mesh quality requirements of subsequent numerical calculations for mechanical analysis.

The application provides an electromagnetic surface wave transmission method based on three-dimensional reconstruction of damage of a wave-absorbing coating, and belongs to the technical field of measurement, and comprises the following steps: microwave heating treatment is performed on a wave-absorbing coating sample with damage, and a surface temperature cloud chart of the sample is obtained through computer processing; a region with a surface temperature of the wave-absorbing coating higher than a test environment temperature is extracted from the surface temperature cloud chart; the extracted region is subjected to triangular face mesh division, and all triangular elements are combined to realize three-dimensional reconstruction of the damage region of the wave-absorbing coating; a surface wave propagation method based on a dispersion equation is constructed; the transmission of surface waves in the three-dimensional reconstruction model of the damage region of the wave-absorbing coating is analyzed by using the dispersion equation, the influence of the thickness of the triangular element and the electromagnetic parameters of the combined model on a surface wave attenuation constant is discussed, and a surface wave attenuation constant model based on three-dimensional reconstruction of damage of the wave-absorbing coating is constructed. The application provides a theoretical basis for damage evaluation of a wave-absorbing coating of an aircraft.

The invention provides a sub-codebook composite codebook generation method and system based on regional similarity clustering, and the method comprises the steps: obtaining a matrix training set based on a channel covariance matrix of a large-scale MIMO system; extracting an upper triangular element of each channel covariance matrix, separating a real part and an imaginary part, and constructing a high-dimensional covariance feature training set; pCA dimension reduction processing is carried out, and a K-Medoids clustering algorithm is combined with contour coefficient optimization and an optimal number of covariance mode clusters are identified; based on the sample density weight, distributing the total code word number to each cluster in the covariance mode cluster according to a proportion, and taking the total code word number as the exclusive code word number of each cluster; obtaining an exclusive sub-codebook corresponding to each cluster; and integrating the exclusive sub-codebooks of all clusters, and constructing a final composite codebook. By extracting the triangular elements on the covariance matrix and separating the real and imaginary parts, the channel covariance mode features are accurately captured, and the adaptive capacity of the codebook to complex propagation scenes with multipath reflection, shielding and the like is effectively improved.

The invention relates to a triangular grid pixelation method for electromagnetic scattering center extraction, and belongs to the technical field of electromagnetic compatibility and antennae. The method comprises the following steps: reading data to obtain a model view, obtaining a point list P and a triangular unit list E of a grid, appointing the point list and triangular units, and obtaining actual direction vectors of a U axis and a V axis of the model view; calculating a projection grid model of the platform grid model on the UOV surface of the model view and an area range of the projection grid model; establishing a two-dimensional rectangular grid model by taking the region range as a boundary and taking the U-axis and V-axis directions as region coordinate axes; and traversing the projection grid model, marking effective pixel points from the rectangular grid units Gij, exporting the list H, the two-dimensional rectangular grid G and the triangular cycle list S to which the two-dimensional grid belongs, and displaying an image of the two-dimensional array grid. According to the method, calculation is simplified through the pixelated grids, and resource consumption can be reduced; a two-dimensional pixel image visually displays scattering center distribution, and analysis and calculation are facilitated.

The present invention relates to a three-dimensional undulating green generation system for realistic putting simulation. The present invention comprises: an input module that sets terrain generation parameters of the green according to the difficulty or set value of the putting simulation; and a green generation module that generates a undulating surface in three-dimensional space based on the terrain generation parameters. In particular, the green generation module is characterized by generating a random field having an irregular height distribution using a spectral density function, and selectively superimposing tilting and stepping elements thereon to generate a three-dimensional green map similar to an actual field. Furthermore, the present invention provides a realistic putting physics environment by precisely tracking the altitude of the ball through natural coordinate calculations based on triangle elements and dynamically correcting the coefficient of friction according to the slope of the green.

The system is designed to generate ordered quadrangular meshes for three-dimensional, non-canonical surfaces. It includes a partitioning unit that divides the input surface into quadrangular fragments. The system features a computational unit connected to the partitioning unit, which transforms each fragment into a topological square using form functions. A subdivision module, linked to the computational unit, assigns and applies different division numbers (n1, n2, n3, and n4) to each side of the square. This process results in various mesh forms, including square, rectangular, and quadrangular elements. The system further includes a mesh generation unit connected to the subdivision module, which constructs an ordered mesh composed of convex quadrangular elements. The generated mesh ensures that neighboring elements have comparable properties, and a triangular element is added if the sum of the division numbers is odd, ensuring consistency and structural integrity in the mesh.

The invention relates to the technical field of rock mechanics and explosion shock, in particular to a numerical simulation method and system for an ore rock crushing process based on an FDEM explosion load, and the method comprises the steps: constructing an ore rock test piece geometric model by using finite element mesh software Gmsh, and carrying out mesh division to obtain a triangular mesh; setting material parameters and explosion load boundary conditions according to the geometric model of the ore rock test piece and the triangular grid; simulating an explosive load applying process based on parameters and boundary conditions to obtain explosive load simulation information, and deducing and establishing a normal contact force and tangential contact force calculation function according to the simulation information; on the basis of the calculation function and node coordinates and speeds of the updated triangular units, coordinate and speed information after nodes of the triangular units are updated is obtained, then a cloud picture is generated, the crack condition is counted, energy changes are analyzed, and crack propagation, stress field distribution and energy evolution results of the ore rock under the blast load effect are obtained. According to the method, a quantitative basis is provided for field blasting parameter selection, and the blasting efficiency and accuracy are improved.

The invention provides a DOA (direction of arrival) estimation method based on cascaded multi-head attention Transformer, and relates to the technical field of array signal processing, and the method comprises the steps: firstly constructing a sampling covariance matrix for array signals received by a uniform linear array, extracting upper triangular elements, and extracting real parts, imaginary parts and phase information to form a group of vectors, thereby obtaining low-redundancy signal representation; then, the vector is mapped into a token sequence, the token sequence is combined with position codes to be input into a cascade multi-head attention converter encoder, and the encoder models the global dependency relationship of array signals through a multi-head self-attention structure increasing layer by layer and extracts deep features; and finally, generating a DOA estimation result on the discrete angle grid through an output layer by using global feature representation of the classification token. Compared with the prior art, the method has the advantages that the global correlation of the array signals can be effectively mined, the DOA estimation precision and robustness are remarkably improved, and the method is widely applied to application scenes such as wireless communication, sound source localization, radar detection and sonar direction finding.

This application provides a method and related equipment for constructing a groundwater flow field based on irrotational conditions. The method includes constructing a groundwater flow model, dividing the internal space of the groundwater flow model into a computational grid comprising multiple triangular elements and multiple nodes; determining the head data of each node other than the observed nodes using a linear interpolation algorithm based on the head data of known observation nodes in the groundwater flow model; and determining the target head data of each node and the target flow velocity corresponding to each triangular element through multiple iterations based on the head data of each node. Based on the water level at observation well points and driven by the physical laws of groundwater movement, this application can quickly and automatically generate a physically reasonable flow field through efficient iterative calculations, providing a powerful new tool for groundwater simulation and analysis.

The present application relates to the technical field of rock dynamics numerical simulation, in particular to a numerical simulation method and system for the whole process of rock and ore fracture under impact load based on FDEM, which comprises the following steps: discretizing the continuous medium structure into a finite element network composed of triangular elements through FDEM, and constructing a rock and ore impact test model; setting material parameters and impact velocity boundary conditions according to the rock and ore impact test model; establishing a normal contact force calculation model and a tangential contact force calculation model according to the material parameters and impact velocity boundary conditions, and obtaining the coordinate and velocity update results of the triangular element nodes in combination with Newton's second law and the calculation model; and performing visual analysis based on the coordinate and velocity update results to output the crack propagation, stress field and energy evolution results under impact load. The present application can accurately simulate the crack propagation, fracture mode and energy evolution law of rock and ore under impact load, quantitatively study the rock and ore crushing characteristics and energy evolution law, and provide a calculation method for the rock and ore crushing mechanism research.

The present application relates to the field of rock mechanics and explosion impact technology, in particular to a numerical simulation method and system for the breaking process of ore rock under explosion load based on FDEM, comprising the following steps: using finite element grid software Gmsh to construct an ore rock specimen geometric model and grid division to obtain a triangular grid; setting material parameters and explosion load boundary conditions according to the ore rock specimen geometric model and the triangular grid; simulating the explosion load application process based on the parameters and the boundary conditions to obtain explosion load simulation information, and deriving and establishing a normal contact force and a tangent contact force calculation function according to the simulation information; based on the above calculation function and the updated node coordinates and velocity of the triangular element, obtaining the updated coordinate and velocity information of the triangular element nodes, and then generating a cloud chart, counting the crack condition and analyzing the energy change to obtain the crack propagation, stress field distribution and energy evolution results of the ore rock under the explosion load. The present application provides a quantitative basis for the selection of on-site blasting parameters, and improves the blasting efficiency and accuracy.

The invention belongs to the field of radar information processing, and particularly relates to a rapid matrix inversion method based on Cholesky decomposition optimization, and the method comprises the steps: carrying out the column principal component Cholesky decomposition of a regularization matrix, and obtaining an arrangement matrix P; calculating lower triangular elements in the arrangement matrix P, performing main diagonal protection on the lower triangular elements, dividing the arrangement matrix P into a plurality of sub-blocks by adopting block recursive calculation, and performing triangular matrix inversion on each sub-block to obtain a symmetric matrix; and performing inversion synthesis on the symmetric matrix to obtain a final inverse matrix. Through improved Cholesky decomposition, the complexity of traditional matrix inversion is reduced, through a block recursion calculation strategy, the cache utilization rate is remarkably increased, memory access delay is reduced, and the actual measurement speed-up ratio reaches 4-8 times. According to the method and the device, the remote weak signal processing capability can be remarkably improved for scenes needing to process remote weak signals, such as micro unmanned aerial vehicles or stealth targets with relatively small RCS, and the frame processing period is effectively shortened on the premise that the performance is maintained.